safari can't establish a secure connection

My business partner was experiencing the same issue from home on a MacBook Pro and iMac on a wireless network - she could not access any google sites or services (google.com, gMail, Google Drive, youtube, etc.). Both machines were running 10.9.5 and upgrading to 10.10 solved the problem. Here is a list of things we tried first which did NOT work:

- added dns 8.8.8.8

- software/security updates (without updating from 10.9 to 10.10)

- turn off extensions in safari

- delete google cookies in safari

- install chrome and firefox; problem was consistent across all browsers

- repair permissions

- boot as a new, different user

- boot into safe mode

- remove startup items

- reset router

- update router firmware

If this is happening on more than one computer, it indicates that the problem lies with either your router or ISP, thus rendering any changes you make to a single computer ineffective. When you added the 8.8.8.8 DNS, did you add it to your router settings or to the network settings on your computer? (should be your router). I can't guarantee that it will work, but it has done for me in the past. Otherwise, I suggest you try calling your ISP and asking them for some additional DNS addresses.

I'm in the same boat.

I've tried deleting cache and cookies, but it did't work for me.

After surfing some websites, I found some tips that worked for me.

Go to System Preferences,choose network

Click "advanced", go to the "Hardware" tab, and click on "configure", choose "manually"

Click on mtu, change it to "custom" and set the mtu number to 1453 (I dont why but the number is something like a networking secret from ancient times)

regards,

<Link Edited by Host>

Amen to this! Spent a week trying to figure out why I could only load certain pages but not others (duckduckgo but not google, no gmail or yahoo mail, etc) and finally ran across this post. I installed Avast a while ago and forgot about it, and for some reason it recently started messing with my internet. Turned off the web shield and now everything works as expected!

I was experiencing the same problem. FB would open once every several attempts. Gmail also. After reading through the thread, I checked AVAST settings. IPV6 was checked. I unchecked it and everything seems to be working ok...

The real issue, is that Apple is not updating Safari's security protocols to interface with websites that are enhancing their own. That's and understatement: the last time I received a Safari update was in August 2014. When I get the message on my desktop that a secure connection can't be established, I go to my tablet and guess what, I have a secure connection. If Apple were as diligent about keeping desktop users software up to date as they are developing new operating systems, there wouldn't be a problem, but, there's no money in it for them to upgrade my Safari 6.1.6 running 10.7.5.

The problem is not limited to Safari - it is computer-wide. Chrome also fails, as does wget from the terminal. I disabled IPv6 and the problem resolved.

I was working on a site I manage at the time, and I have asked for help to ensure that the Website and all its constituent components - AT&T firewall, Akamai, lots of intermediate actors - are fully IPv6 enabled. This is going to be an on-going problem for us all over the next few years as we transition to more and more https and more and more IPv6 - getting all the gears aligned will take time and consternation.

Thanks seeburg220. I was having a problem just with one website. From your post I was able to quickly discover that Avast Web shield was the problem.

All I had to do to was go to Avast > Preferences > Shields > Web Shield > Settings, then under Excluded servers add the url of the site it wasn't giving me access to. Job done!

My problem is with Safari and only with Google sites, e.g. Google search just hangs showing a blank page. It happens either when the mac has been asleep or if the underlying internet connection was reconnected for example if the ADSL modem needed restarted but not the airport extreme thus WiFi stayed connected. I believe it is a bug in Safari's DNS caching affecting the SSL connection not being re-connected perhaps because Google's IP changes due to their load balancing when either of those things happen, and perhaps Google is not allowing the original SSL connection to be reconnected to its new server IP. Or it could be an SSL certificate problem. Either way Safari has the bug since other browsers are not affected.

I was having the same problem. I have spent the last day trying to find the right resolution. I found a link to another forum and they recommended that you delete the

~/Library/Preferences/com.apple.security.plist

I haven't had the problem for a while now and I'm pretty sure I fixed it by doing this:

In Keychain search for Geotrust Global CA, mark it "never trusted" close it enter password to save, then mark it "Use system default" and close it and save again. This is the CA that google use for its certifications. You can confirm it by clicking the padlock in the Safari address bar when at google.com

I learned the solution from this Danish guy who had the exact same problem but with Twitter, so he had to do it to the Verisign CA instead.

This doesn't always fix this issue. I deleted all my certificates and then reloaded them (I use PKard to do this). I still can only access certain PKI-enabled SharePoint sites and others fail to load ("could not establish a secure connection.").

I thought this was a likely explanation as well...but it doesn't explain why I can still access certain PKI-enabled MS SharePoint sites from my iMac and not from my MBP.

I access two US Government PKI-enabled MS SharePoint sites, both administered by separate domains. I am able to access both MS SharePoint sites on my iMac - yet when I try to access both from my MBP, only one is accessible. So I think it is safe to assume that security protocols are not the issue with me. Both Macs are running the latest OS X are up to date.

Deleting the Cache.db file and removing all website data didn't work. The Firewall doesn't seem to be affecting the site - I have turned the firewall off and tried to access the site, and it didn't work.

OMG I finally fixed my problem with this!!!

I had this come up for the past 4 days and have searched EVERYWHERE to find out how to fix it. I then found a suggestion and thought "i've literally tried everything so why not" It said that my date and time might be off and to turn on auto date and time in the General Tab on my iPad (iOS 10.0.2). I did it and it was fixed!!!! I was so frustrated reading the Apple support questions with no help to my proble. So I REALLY hope this helps someone!